1. Field of the Invention
The present invention relates to a semiconductor manufacturing apparatus and a method of manufacturing a semiconductor device. The invention relates, for example, to a semiconductor manufacturing apparatus which comprises a peeling mechanism to peel a pressure sensitive adhesive tape adhering to a semiconductor wafer, and a method of manufacturing a semiconductor device using a semiconductor manufacturing apparatus according to the invention.
2. Related Background Art
Generally in a manufacturing process of a semiconductor device, a semiconductor wafer on which element formation has been finished is divided and separated into pieces along a dicing line or a chip division line, thereby forming a plurality of semiconductor chips. A pressure sensitive adhesive tape (which will be hereinafter referred to as a PSA tape) is affixed to the semiconductor wafer before and after the chip separating process, and the semiconductor chips in the piece form are integrated to keep a wafer shape. The semiconductor wafer, which has thus been broken into a plurality of semiconductor chips and is supported by the PSA tape, is transferred to a mounting process using, for example, a die bonder (refer to FIG. 2). Each semiconductor chip separated from the semiconductor wafer is picked up from the PSA tape, and undergoes a mounting process such as a process of mounting to a leadframe or a TAB tape or a process of sealing into a package, thereby completing the semiconductor device.
When such individual semiconductor chips are picked up, a surface of the semiconductor wafer, opposite to a surface to which the PSA tape is affixed, is affixed to another PSA tape which is affixed to a wafer ring, and then the PSA tape is peeled off, and the wafer ring is mounted to a pickup device to pick up the individual semiconductor chips.
FIG. 55 is an enlarged sectional view of essential components of a conventional pickup device in picking up a semiconductor chip 100 from a PSA tape 101, which is disclosed in Japanese Patent Publication Laid-open No. 2003-17513. When the semiconductor chip 100 is peeled off and picked up from the PSA tape 101 affixed to the wafer ring, thrust pins (or pick-up needles) 102 are pushed up (raised) via the PSA tape 101 from a rear surface side of the semiconductor chip 100, and elasticity of the PSA tape 101 is utilized to peel off the semiconductor chip 100. The thrust pins 102 are disposed at corner portions or positions corresponding to the vicinity of a central portion of the semiconductor chip 100, and the base of the thrust pins 102 are attached to a pin holder 103.
As an order to peel off the semiconductor chip 100 from the PSA tape 101, a holding table, on which the PSA tape 101 to which the semiconductor chip 100 is affixed is fixed, is first moved so that the semiconductor chip 100 to be picked up will be located above the thrust pins 102. Next, for example, detection of a position of the semiconductor chip 100 to be peeled off and mark detection for identification of non-defective/defective products are performed, and an internal portion of a backup holder 104 is sucked by vacuum to cause the PSA tape 101 to be sucked and fixed onto an upper surface of the backup holder 104. In this state, the pin holder 103 to which the thrust pins 102 are mounted is lifted to project the thrust pins 102 from the upper surface of the backup holder 104 and raise the semiconductor chip 100 via the PSA tape 101 from the rear surface side. The raised semiconductor chip 100 is held by a suction collet 105 and supplied to the mounting process.
There has recently been a keen desire for a thinner semiconductor chip, for example, to have the semiconductor chip built in a thin card-shape package, and the thickness of the semiconductor chip is reduced to 100 μm or less by polishing, grinding and etching a rear surface of the semiconductor wafer.
Problems with the cracks which might happen when the thickness of the semiconductor chip is thus reduced to 100 μm or less will be described in more detail referring to FIGS. 56A to FIGS. 57B.
With the thickness of the semiconductor chip being very small as described above, even if an outer peripheral portion (corner portions in particular) of the semiconductor chip 100 comes off from the PSA tape 101, the semiconductor chip 100 warps in a concave shape before being peeled off as shown in FIG. 56A because a speed at which the PSA tape 101 is peeled off is slower than a speed at which the thrust pins 102 are lifted, and is finally cracked as shown in FIG. 56B. Further, as shown in FIG. 57A, if the rear surface side of the semiconductor chip 100 is raised with the thrust pins 102 via the PSA tape 101, cracks are caused in portions of the semiconductor chip 100 that contact the thrust pins 102 with only the corner portions being peeled off, or the thrust pins 102 penetrate as shown in FIG. 57B, leading to a crack of the chip. If the thickness of the semiconductor chip is 100 μm or more, such phenomenon is less likely to occur since strength (thickness direction) of the semiconductor chip is higher than a force of adhesion to the semiconductor chip 100 of the PSA tape 101.
If the thickness of the semiconductor chip is thus reduced, deflecting strength of the semiconductor chip is decreased. Moreover, quality deterioration such as the cracks and chipping, and a lowering yield ratio can not be avoided with a conventional mechanism and method of peeling the PSA tape and a conventional device and method for picking up the semiconductor chip. Therefore, improvement has been desired not only in such a mechanism, device and methods, but also in an apparatus and method of manufacturing the semiconductor device comprising the above.
Especially, when an adhesive, an adhesive sheet or an adhesive film adheres to the rear surface or element formation surface of the semiconductor chip, load is higher during peeling off and fracture is more frequently caused, resulting in a problem of the quality deterioration and lowering yield ratio in the semiconductor device.